1. Field of the Invention
This invention relates to a time information generator for generating time information in an arbitrary frame of video information varying with changes in time, and more particularly to a time information generator for generating time information by interpolative processing.
2. Description of the Prior Art
Generally, in video editing systems, in the case of controlling an equipment such as a video tape recorder, etc. by an editing machine, a time code signal as described in, e.g., U.S. Pat. No. 4,159,480 is used as time information indicating a recording position of a video signal processed by that equipment. In such a video editing system, so called a mark processing, etc. is conducted to read, e.g., a value of a time code on a video tape to display that value on a visual display screen, or take a time code at an arbitrary time into the editing machine.
In the above-mentioned video editing system, it is desirable to sense the time code as frequently as possible in equipment such as a video tape recorder, etc. in order to provide a precise time information at an arbitrary time in the editing machine. Since video information, i.e., video signals processed by the above-mentioned video tape recorder, etc. are constructed per each frame, the sensing of the time code is conventionally conducted every frame in the editing machine.
Further, also in the digital video effector for adding the video effect to a video signal outputted from a video tape recorder, etc., some video editing systems use time codes as position information for providing a special effect.
Meanwhile, some equipment such as video tape recorders, or digital video effectors, etc. controlled by an editing machine in the video editing system is constructed to suppress the response processing ability with respect to external devices in order to ensure the processing ability for the original video processing in the equipment body or the system control. In such equipment, there are instances where even if an approach is employed to carry out the sensing of time codes every frame in the editing machine, the result is not satisfactory. Accordingly, it is necessary to sense the time codes once per several frames to widen the sensing interval.
However, if the sensing interval is widened, the updating interval of time information displayed on the display screen becomes coarse, resulting in bad impression or lowered accuracy in controlling a video tape recorder, etc.
With the actual circumstances in the above-described video editing system in view, this invention contemplates providing a time information generator capable of generating a time code at an arbitrary time even if the sense interval is widened with respect to equipment having a lower response processing ability.